registry / Install hook abuse / juanig
juanig
Download Instagram photos, carousels, videos, and Reels from a link.
This report shows the evidence for juanig@1.1.3, the only known version.
AI Security Review
scanned 1mo ago · by lpm-firewall-aiThe package performs automatic postinstall writes into multiple third-party AI-agent skill locations. This meets the install-control-surface blocking rule even though the media downloader itself is otherwise package-aligned.
Static reason
One or more suspicious static signals were detected.
Trigger
npm installation executes postinstall.
Impact
Package instructions are injected into Cursor, Claude, Windsurf, Continue, and agent project skill locations, influencing future agent behavior.
Mechanism
Automatic cross-tool AI-agent skill installation.
Attack narrative
During npm installation, postinstall runs pip on the bundled project and then invokes --install-skills. That code detects several existing third-party AI-agent directories in the home directory or current project, creates a juanig skill subdirectory, and writes its packaged SKILL.md there. This is an unconsented install-time mutation of a broad foreign AI-agent control surface.
AI rationale
The package performs automatic postinstall writes into multiple third-party AI-agent skill locations. This meets the install-control-surface blocking rule even though the media downloader itself is otherwise package-aligned.
Evidence
npm/postinstall.jsjuanig/setup_local.py~/.cursor/skills/juanig/SKILL.md~/.claude/skills/juanig/SKILL.md~/.codeium/windsurf/skills/juanig/SKILL.md~/.continue/skills/juanig/SKILL.md~/.agents/skills/juanig/SKILL.md.cursor/skills/juanig/SKILL.md.claude/skills/juanig/SKILL.md.agents/skills/juanig/SKILL.md
Decision evidence
public snapshotAI called this Malicious at 98.0% confidence as Malware with low false-positive risk.
Evidence for block
- The npm postinstall hook installs the bundled Python project and automatically invokes its skill installer.
- The installer targets skill locations for several third-party AI coding tools in both the user home directory and the current project.
- The skill installer creates directories and writes package-provided instructions into those agent control locations.
Evidence against
- The inspected downloader sends its optional session cookie only to Instagram endpoints used for the requested media download.
- No hidden endpoint, payload download, self-dependency, or credential-exfiltration path was found in the inspected source.
Behavioral surface
ChildProcess
Source & flagged code
7 flagged · loading sourcepackage.jsonView file
•scripts.postinstall = node npm/postinstall.js
High
Install Time Lifecycle Scripts
Package defines install-time lifecycle scripts.
package.jsonView on unpkg9"scripts": {
"postinstall": "node npm/postinstall.js"
},
High
Suspicious Lifecycle Evidence
The npm postinstall hook installs the bundled Python project and automatically invokes its skill installer.
package.jsonView on unpkg · L9•scripts.postinstall = node npm/postinstall.js
Medium
Ambiguous Install Lifecycle Script
Install-time lifecycle script is not statically allowlisted and needs review.
package.jsonView on unpkgjuanig/update.pyView file
Findings
5 High3 Medium1 Low
HighInstall Time Lifecycle Scriptspackage.json
HighSuspicious Lifecycle Evidencepackage.json
HighSuspicious Lifecycle Evidencenpm/postinstall.js
HighAi Review Evidencejuanig/setup_local.py
HighAi Review Evidencejuanig/setup_local.py
MediumAmbiguous Install Lifecycle Scriptpackage.json
MediumShips Build Helperjuanig/update.py
MediumStructural Risk Force Deep Review
LowScripts Present
Affected versions and remediation
This report applies to juanig@1.1.3.
The versions list below shows the verdict for each recorded version.
- Avoid installing juanig@1.1.3. Remove it from direct dependencies and check your lockfile for transitive copies.
- Choose an independently verified alternative or release. This report does not establish that other versions are safe.
- If this version ran, investigate the affected machine and build environment. Rotate credentials it could access and rebuild from a trusted environment.
Evidence last updated: .
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